Hydraulic latch pin assembly for coupling a tool to a construction equipment

ABSTRACT

The invention provides a coupling assembly and method for coupling a tool to a dipperstick, or arm, on an apparatus which has a hydraulic system for moving the tool. The coupling assembly includes a coupler body having link structure for pivotally coupling to the dipperstick. A latch member is movable between an engaged position for engaging the tool and a disengaged position for disengaging from the tool. A spring is arranged to provide a spring force to urge the latch member to the engaged position. A hydraulic motor has a part that is stationary relative to the coupler body and a movable part that can be extended relative to the stationary part when hydraulic pressure is applied to one end of the hydraulic motor. The movable part is coupled to the latch member such that extension of the movable part urges the latch member to the retracted position in opposition to the spring force.

This is a continuation of application Ser. No. 08/634,561, filed Apr.18, 1996, now U.S. Pat. No. 5,727,342.

BACKGROUND OF THE INVENTION

The invention relates to tool couplers for excavation, demolition andconstruction equipment.

Some types of construction equipment, such as backhoes and excavators,have a movable dipperstick (also referred to as an arm) to which avariety of tools, such as, for example, buckets and grapples, can beattached. A hydraulic linkage allows the equipment operator to pivot thetool from the free end of the dipperstick. To simplify the process ofchanging tool attachments, a universal coupler can be fixed to thedipperstick linkage. A selected tool can then be removably attached tothe coupler, a process that typically involves manually positioning atleast one latch pin between the coupler and the tool.

There is a trend in the industry to use an actuated coupler on the endof the dipper stick for connecting and disconnecting a tool from thelinkage. A great advantage of these systems is that the operator canactuate the coupler to connect or disconnect a tool without theassistance of another worker and without having to leave the cab of thevehicle.

One type of actuated coupler first engages a crossbar formed in the toolwith hooks depending from the coupler, and then engages a latch pin (ora block or a wedge) with a mating receptacle formed in a collar on thetool. A double-action hydraulic cylinder in line with the latch pin ispositioned so that the cylinder extends to push the latch pin into thereceptacle. In disengaging the tool from the coupler, the operatorretracts the rod into the cylinder body, pulling the pin out of thereceptacle.

SUMMARY OF THE INVENTION

The invention provides a coupling assembly for coupling a tool to adipperstick, or arm, on an apparatus which has a hydraulic system formoving the tool. The coupling assembly includes a coupler body having aframe that defines a central cavity, and also having link structure forpivotally coupling to the dipperstick. An actuator assembly positionedwithin the central cavity includes a latch pin movable between anextended position and a retracted position. In the extended position, anend of the latch pin projects rearward from an opening in a rear end ofthe frame for engaging an aperture or receptacle defined by the tool. Inthe retracted position, the end of the latch pin is disengaged from thetool receptacle and positioned substantially within the frame. Theactuator assembly also includes a hydraulic latch cylinder that has amovable part, and a fixed part. The movable part is coupled to the latchpin by a latch pin coupling assembly, which is structured and arrangedsuch that, when the movable part is extended from the fixed part, thelatch pin moves to the retracted position.

According to another aspect of the invention, the latch pin couplingassembly includes a bias member structured and arranged to apply a biasforce that urges the latch pin towards the extended position. When athreshold level of hydraulic pressure is applied to the latch cylinder,the movable part of the cylinder overcomes the bias force and extends tomove the latch pin to the retracted position and out of engagement withthe tool.

Another feature of the invention is that the latch cylinder can be asingle-action cylinder.

According to another feature of the invention, the latch cylinder can bepositioned on an axis different from an axis defined by the latch pin,such as along side the latch pin. This feature provides a compactarrangement. The system is easily adaptable to any type of quick couplertype system due to the compactness and placement of the actuatingcylinder.

According to another feature of the invention, the hydraulic pressure tothe latch cylinder can be controlled by an electrically actuated valveassembly that hydraulically couples the dipperstick hydraulics to thelatch cylinder. The valve assembly can include one or more solenoidvalves that only allow hydraulic pressure to enter and remain in thelatch cylinder when they are energized.

According to another feature of the invention, the valve assembly can bestructured and arranged such that the dipperstick hydraulics must beapproximately fully pressurized while extended to pressurize the latchcylinder.

According to another feature of the invention, the coupling assembly canalso include a pin indicator that readily shows whether the latch pin isretracted. The indicator is located such that it can be viewed easilyfrom the operator position.

According to another feature of the invention, a drop in hydraulicpressure in the latch cylinder below the threshold level allows the biasspring to push the coupling pin towards the extended position. Anunexpected hydraulic pressure loss can be caused by a failure in thehydraulic system or by a failure in the valve assembly. The springapply, hydraulic release system is safe in that it assures that anattached tool will not accidentally uncouple from the coupling assemblyif there is a loss in hydraulic pressure in the latch cylinder.

The invention also provides a method of removing a tool from the couplerassembly having features as described above. An operator can remove atool by the steps of applying hydraulic pressure to a latch cylinderthat has a part fixed relative to the coupler body and a movable partrigidly coupled to the latch pin, extending the movable part from thefixed part, thereby urging the latch pin to the retracted position,engaging a cross member of the excavation tool with a hook structuredepending and extending forward from the coupler body, rotating thecoupler body toward the tool, aligning the latch pin with a matingreceptacle formed in the excavation tool, reducing hydraulic pressure tothe latch cylinder, and applying a bias force to the latch pin, urgingthe latch pin to the engaged position, thereby engaging the latch pin inthe receptacle and securing the excavation tool to the coupler body.

According to another aspect of the invention, the method furtherincludes the step of removing the tool from the coupler, includingrotating the coupler body and the tool to a full forward position, againapplying hydraulic pressure to the latch cylinder, again extending themovable part from the fixed part, thereby urging the latch pin to theretracted position and disengaging the latch pin from the receptacle,and disengaging the hook structure from the cross member of theexcavation tool.

The latch cylinder extends using the more powerful head end to extractthe latch pin, whereas coupling systems using an in-line dual-actioncylinder and latch pin arrangement use the less powerful rod end forthis purpose. This feature of the invention is important when extractinga frozen pin, which can require substantially more force than insertinga free moving pin.

Since, the hydraulic system uses a single-action latch cylinder, it onlyrequires one hydraulic line between the valve assembly and the latchcylinder. This is simple and inexpensive compared with coupling systemsthat use a dual-action cylinder, and that require two hydraulicconnections.

The rod of the latch cylinder is normally in the retracted positionduring the tool working period. Because the latch cylinder is retracted,the rod of the latch cylinder is not subject to damage from rocks andsharp objects. Normally, the only time the rod is extended, and therebyexposed to the elements and contaminants, is when a tool is beingattached or detached from the coupling assembly.

A feature of the invention is that if there is a loss of eitherelectrical or hydraulic power, the latch pin will extend or “insert”automatically. If electrical power inadvertently gets to the solenoidvalves, the tool has to be fully rolled forward and inward in order forthe pressure to build up in the latch cylinder to retract the latch pin.In this position, the coupler hooks are fully engaged and the likelihoodof the tool falling off is minimized. One cannot simply throw the switchand have the tool fall to the ground.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of dipperstick with an attached couplingassembly, and a conventional bucket that can be attached to the couplingassembly.

FIG. 2 is a side view of a hydraulic coupling assembly shown coupling aconventional bucket to a dipperstick.

FIG. 3 is a top plan view of a coupling assembly, partially showing abucket, with the latch pin in an unlatched, retracted position. FIG. 3Ais a similar view, partially broken away, showing the latch pin in alatched, extended position.

FIG. 4 is a section view through line 4—4 of FIG. 3. FIG. 4A is asimilar section view through line 4A—4A of FIG. 3A.

FIG. 5 is a partial section view through line 5—5 of FIG. 3. FIG. 5A isa similar partial section view through line 5A—5A of FIG. 3A.

FIG. 6 is a schematic diagram of a hydraulic system and an electricalsystem according to the invention. FIGS. 6A, 6B and 6C illustrate otherembodiments of a valve assembly.

In the following detailed description of the invention, similarstructures that are illustrated in different figures will be referred towith the same reference numerals.

It will also be noted that the figures are generally not drawn to scale.

DETAILED DESCRIPTION OF THE INVENTION

Referring first to FIGS. 1 and 2, a hydraulic coupler assembly 10according to the invention is attached to a conventional dipperstick orarm 12. Only a free end of dipperstick 12 is illustrated in FIGS. 1 and2. The other end of dipperstick 12 is pivotally coupled, typically viaan intermediate articulation (not shown), to a base (not shown) thatincludes a hydraulic power system, and hydraulic and electric operatorcontrols located in a cab. Coupler assembly 10 can be used for couplingthe dipperstick 12 to any of a variety of tools, such as, for example, aconventional bucket 14.

Dipperstick 12 linkage includes a bucket guide link 16 pivotallyattached to the dipperstick 12, a bucket cylinder 18 for actuating thecoupling assembly 10 and the bucket 14, and a bucket link 20. Extendingbucket cylinder 18 rotates coupling assembly 10, and any tool attachedto coupling assembly 10, inwardly in a forward direction.

Referring now also to FIGS. 3-5, coupling assembly 10 includes a frame24 forming a central space 22. Frame 24 includes side walls 26, a bottomplate 28, a coupler spreader plate 30 and a rear face plate 32.Depending from side walls 26 are a pair of forward extending hooks 34that are adapted to fit through an opening or recess 36 formed in a backsheet 38 of bucket 14 (see FIG. 1). The hooks 34 can then engage a crosstube 40 to support a forward end of bucket 14.

Coupling assembly 10 has a pair of dipper pivot fixtures 42, locatednear a forward end of side walls 26 for coupling to dipperstick 12. Apair of link pivot fixtures 44 for coupling to bucket link 20 arelocated closer to the rear end of the frame 26. A pair of link pivotfixtures 46 are also provided at an alternate location.

Bucket 14 is adapted to be coupled to dipperstick 12 with couplingassembly 10. As noted above, a recess 36 is formed in back sheet 38 ofthe bucket for receiving hooks 34. Once cross tube 40 is engaged byhooks 34, the bucket can be lifted off the ground by raising thedipperstick 12. This connection provides a first point of connectionbetween coupling assembly 10 and bucket 14. To enable the bucket 14 torotate by operation of the bucket hydraulic cylinder 18, a receptacle 50formed in a latch collar 51 fixed to a plate 52 on the rear end ofbucket 14 engages one end of a movable latch pin 48.

Latch pin 48 slides within the bore of a bushing 60 welded to rear faceplate 32 within frame 24. On the other side of plate 32 there is anapproximately semicircular-shaped coupler crescent 61 that fits over thetop of latch collar 51 when bucket 14 is attached to coupling assembly10.

The latch pin 48 is part of an actuator assembly 54 that also includes acoil spring 56, or other type of compression spring, for pushing thelatch pin 48 through bushing 60 into engagement with the receptacle 50,and a single-action latch pin hydraulic cylinder 58 that acts oppositethe spring 56 to disengage the latch pin 48 from the receptacle 50.Spring 56 is positioned approximately in line with latch pin 48, andlatch cylinder 58 is positioned on a parallel axis along side latch pin48 and spring 56. This arrangement allows the cylinder 58 to “push” thepin 48 out to retract. The spring 56 urges the pin 48 toward an engagedposition with receptacle 50 when hydraulic pressure in the latchcylinder 58 is insufficient to overcome the spring force of spring 56.The latch pin 48 is normally in the engaged position because latchcylinder 58 is normally not pressurized.

Coil spring 56 is kept in position by a latch spring assembly that formspart of actuator assembly 54. One end of coil spring 56 bears against apin block 62 that is welded to latch pin 48. Pin block 62 includes anannular groove to receive coil spring 56. The other end of coil spring56, towards the front of coupler 10, bears against a winged end plate 64and thereby holds the winged end plate 64 within the “V” formed bycoupler spreader plate 30. A spring guide rod 66 is positioned withinthe coils of spring 56. Spring guide rod 66 extends transversely througha hole formed in end plate 64 and is welded thereto. A forward end ofspring guide rod 66 includes a notch 68 that is positioned against anangled top edge 69 of coupler spreader plate 30 and held in place by thespring force from spring 56. The other end of spring guide rod 66 actsas a stop for latch pin 48 in the retracted position (see FIG. 4).

The body 70 of latch cylinder 58 is fixed to pin block 62. In theembodiment illustrated in FIGS. 3-5, body 70 has screw threads formed onits outer surface and screws into mating threads formed in a throughhole in pin block 62, and is held in place by a set screw 71. Thecylinder's extensible rod, or piston 72, extends through the hole in pinblock 62. When hydraulic pressure coupled into cylinder 58 throughhydraulic fitting 73 is increased, cylinder 58 extends and the free endof piston 72 bears against push plate 74, which is welded to bushing 60.

Extension of cylinder 58 with sufficient force to overcome spring's 56spring force thereby urges latch pin 48 to a retracted position sincelatch pin 48 is welded to pin block 62 and pin block 62 is fixed tocylinder body 70. Release of pressure in cylinder 58 allows spring 56 toextend, urging pin block 62, and thereby latch-pin 48, toward a latchedposition wherein the latch pin 48 projects beyond rear face plate 32.

Pin block 62 includes a cylindrical opening 76 that receives springguide rod 66 when latch pin 48 is retracted by actuation of cylinder 58(see FIG. 3). As mentioned above, spring guide rod 66 stops latch pin 48from retracting beyond a predetermined point. When latch pin 48 is fullyretracted, the end of spring guide rod 66 is inside the cylindricalopening 76 in pin block 62 and projects beyond the corresponding end ofspring 56. In this position, a transverse assembly hole 78 formed in theend of spring guide rod 66 is aligned with a U-shaped slot 80 formed inpin block 66. An assembly pin (not shown) can be placed in assembly hole78. When pressure in cylinder 58 is released, latch pin 48 can bemanually moved to the latched position, thereby releasing spring guiderod 66 from cylindrical opening 76 in pin block 62. Assembly pin in hole78 keeps spring 56 compressed on spring guide rod 66. With pin block 62out of the way, the assembled latch spring assembly, comprised of springguide rod 66, spring 56, and winged end plate 64, can be removed as aunit from coupler 10. The latch spring assembly can be installed incoupler 10 by a reverse procedure.

Coupler 10 is structured to allow an operator in the control cab of theconstruction equipment to visibly assess whether the latch pin 48 is inthe latched or retracted position, even when a tool is attached tocoupler 10. Back sheet 38 of bucket 14 extends forward only to theattachment point of hooks 34, which leaves the forward portion of bucket14 open between back sheet 38 and cross tube 40. Bottom plate 28 offrame 24 forms a U-shaped indicator slot 82 positioned between hooks 34.Indicator slot 82 is positioned such that pin block 62 is visiblethrough the opening in bucket 14 and through indicator slot 82 whenlatch pin 48 is in the retracted position. When latch pin 48 is in thelatched position, the operator's line of sight to pin block 62 isblocked by back sheet 38. Pin block 62 can be made more noticeable bypainting it a bright color.

Referring now also to FIG. 6, a hydraulic circuit 86 for operating latchcylinder 58 taps into the hydraulics of the excavator. A hydraulic pump88 and a reservoir 90 are coupled to bucket cylinder 18 via alever-operated, three-position, two-pole valve 92. Pump 88, reservoir 90and valve 92 are located in the base 93 of the excavator. Hydraulichoses 94, 96 connect between valve 92 and the rod end 98 and cylinderend 100 of bucket cylinder, respectively. Hydraulic hose 96 has aT-connection leading to one port of a valve assembly 102. TheT-connection can be conveniently made at the hydraulic fitting for thecylinder side 100 of bucket cylinder 18. The other port of valveassembly 102 connects via hydraulic hose 104 to fitting 73 in latchcylinder 58. Valve assembly 102 can be strapped, bolted or otherwiseattached to a fixed part of bucket cylinder 18 or to an upper portion ofdipperstick 12.

Valve assembly 102 includes two solenoid actuated valves 108, 110, eachwith a power connection controlled by a locking electrical toggle switch111 located in the cab of the excavator. In an unlatch switch positionthe solenoids are energized and in a latch switch position the solenoidsare shut off. When the solenoids are not energized (see FIG. 6), springs112, 114 urge valves 108, 110, respectively to a position wherein acheck valve portion 116 of valve 108 and a through portion 118 of valve110 are connected in series between lines 96 and 104. When valves 108,110 are energized (not shown), a through portion 120 of valve 108 and acheck valve 122 portion of valve 110 are-placed in the circuit.

Check valve 116 blocks a hydraulic flow from bucket cylinder 18 to latchcylinder 58, but is set to permit flow in the other direction when thereis an over-pressure condition in the latch cylinder 58 relative to thecylinder side 100 of bucket cylinder 18. Check valve 122, on the otherhand, blocks any back flow from latch cylinder 58 to bucket cylinder 18,and is set to permit the latch cylinder 58 to be pressurized when thecylinder side 100 of bucket cylinder 18 is fully pressurized. With thecylinder side 100 fully pressurized, bucket cylinder 18 will be fullyextended and the coupling assembly 10 will be rotated fully forward.

Referring now to FIG. 6A, another embodiment of a valve assembly 102′includes valve 108 in series with check valve 124 between lines 96 and104. Check valve 24 prevents back flow from line 104 to 96. A drain line126 normally connects between line 104 and reservoir 90 via throughportion 128 of solenoid valve 130. When valves 108 and 130 areenergized, drain line 126 is blocked by check valve portion 132 of valve130, and through portion 120 is positioned in series connection withcheck valve 124 between lines 96 and 104. Check valve 124, similar tocheck valve portion 122, is set to permit pressurization of line 104 andlatch cylinder 58 when full hydraulic pressure is applied to extendbucket cylinder 18.

Referring to FIG. 6B, in a third embodiment, valve assembly 102″ isconfigured with solenoid valves 108 and 110, similar to the arrangementof valve assembly 102. In addition, a drain line 134 connects betweenvalves 108 and 110. Flow through drain line 134 to reservoir 90 islimited by an orifice 136 flow limiter.

Referring now to FIG. 6C, a fourth embodiment of a valve assembly 102′″includes solenoid valves 138 and 110. In the normal, non-energizedconfiguration shown in the drawing, cylinder 58 drains to reservoir 90via through portion 118 of valve 110 and lower through portion 140 ofvalve 138. When valves 110, 138 are energized, pressure line 96 iscoupled to cylinder 58 via upper through portion 142 of valve 138 andcheck valve portion 122 of valve 110.

Valve assemblies 102′, 102″ and 102′″ can be safer than valve assembly102, especially in high back pressure systems, because of the drainconnections to reservoir 90, however, the drain connections require anadditional hydraulic hose.

Referring again to FIG. 6, indicator lights 148 and an audible indicator144, such as a beeper sound device, located in the cab alert theoperator that the switch 111 is in the energized, unlatch position. Awarning lamp 146 mounted on the dipperstick 12 lights or flashes to helpto alert surrounding personnel that the switch 111 is in the unlatchmode and that the latch pin 48 could be retracted. Of course, audibleindicator 144 can be configured to be audible outside the operator cab.

A single operator in the cab of the excavation equipment can detach atool, such as bucket 14, to the coupling assembly 10 and attach a newtool to the coupling assembly without any assistance, as described indetail below. Some particulars of the following recitation of steps forcoupling and removing a tool are made with reference to the embodimentof valve assembly 102 illustrated in FIG. 6. It will be understood thatthe embodiments of valve assemblies 102′, 102″, and 102′″ illustrated inFIGS. 6A, 6B, and 6C, respectively, will function in much the samemanner, and the operator will make essentially the same sequence ofsteps to attach or detach a tool.

To decouple a tool from coupling assembly 10, the latch pin 48 must bemoved to the retracted position. The operator first throws switch 111 inthe cab to the unlatch position. The indicator lamps 148 and warninglamps 146 then light up, and the audible indicator 144 sounds. Thesolenoids becomes energized, which moves solenoid valves 108, 110 invalve assembly 102 to their unlatch position. Check valve 116 is movedout of hydraulic circuit 89 and check valve 122 is moved into hydrauliccircuit 89. This, by itself, is insufficient to retract latch pin 48.Check valve 122 is set to prevent passage of hydraulic fluid and thusprevent latch cylinder 58 from being pressurized until the pressure onthe cylinder side 100 of bucket cylinder 18 is greater than apredetermined value.

In the illustrated embodiments, check valve 122 is set such that thecoupling assembly 10 and attached tool 14 must be rotated fully forwardand approximately full pressure must be applied in line 96 to bucketcylinder 18 to open check valve 122. This assures that accidentallythrowing switch 111 will not, by itself, be sufficient to retract latchpin 48.

Once the pressure in latch cylinder 58 is great enough to overcome thespring force of spring 56, latch cylinder 58 extends and therebyretracts latch pin 48. The operator can confirm that the latch pin 48 isretracted if he sees the pin block 62 in the retracted position. Whilethe switch 111 is still in the “tunlatch” position, the latch pin 48will be held back retracted.

Alternatively, to bring the latch pin 48 to the retracted position, theoperator can first rotate coupling assembly 10 forward, fully pressurizebucket cylinder 18, and then throw switch 111 to the unlatch position.

At this point, solenoid valves 108, 110 are still energized and in theunlatch position, and check valve 122 retains pressure in latch cylinder58. The operator can then use free hands to maneuver the vehicle todisengage the hooks 34 from cross member 40 to uncouple the tool.

If the equipment is to remain idle for a period of time, the operatorthrows toggle switch 111 to the latch position, de-energizing thesolenoid valves in valve assembly 102, and lowers hydraulic pressure inline 96. This allows pressure to drop in latch cylinder 58 such thatspring 56 urges latch pin 48 to the engaged, or latched position,thereby bringing the piston 72 of cylinder 58 to a protected positionretracted into cylinder body 70.

To attach a new tool, with the latch pin 48 still in the retractedposition and the valves in the valve assembly 102 still energized, theoperator adjusts pressure in the bucket cylinder 18 and maneuvers thecoupling assembly 10 to insert hooks 34 into the recess 36 of the newtool and engage cross tube 40. The operator then lifts the tool off theground, and rolls coupling assembly 10 forward by extending bucketcylinder 18. Coupler crescent 61 engages an upper side of latch collar51, thus bringing latch pin 48 into alignment with receptacle 50 onbucket 14. The operator knows that the coupler crescent 61 has engagedlatch collar 51 when he sees the bucket 14 visibly begins to rollforward. Less than full pressurization of the bucket cylinder 18 istypically required to bring the coupling assembly to this position.

The operator then throws switch 111 to the latch position. Thisde-energizes solenoid valves 108, 110 and moves check valve 122 out ofhydraulic circuit 86 and check valve 116 into hydraulic circuit 86.Check valve 116 is set to open at a low differential pressure, such thathydraulic pressure will be released from the latch cylinder 58 when theback pressure in bucket cylinder 18 is much less than full pressure butgreat enough to rotate coupling assembly forward so that the couplingcrescent engages the tool latch collar 50.

When the hydraulic pressure in latch cylinder 58 is released, spring 56moves latch pin 48 into the engaged position with receptacle 50. Theposition of pin block 62 gives the operator a visible signal that thepin 48 is latched and the tool secured. Check valve 116 thereafterprevents the latch pin assembly from being inadvertently pressurized.

Other embodiments of the invention are within the scope of the followingclaims.

What is claimed is:
 1. An assembly for urging a latch member of toolcoupler into and out of engagement with a tool that is detachable fromthe tool coupler, comprising: a hydraulic motor on the tool coupler, thehydraulic motor having a stationary part and a movable part that extendsfrom the stationary part when hydraulic pressure is applied to one endof the hydraulic motor; a latch coupling assembly coupling between alatch member and the movable part of the hydraulic motor, structured andarranged to urge the latch member to a disengaged position when themovable part is extended; a valve assembly operably coupled to the oneend of the hydraulic motor, including a first position operably couplingthe one end of the hydraulic motor to a fluid drain line to allow fluidto flow through the fluid drain line to a drain from the hydraulic motorwhile preventing fluid flow toward the hydraulic motor, whereby the oneend of the hydraulic motor can be depressurized with the valve assemblyin the first position, and a second position operably coupling the oneend of the hydraulic motor to a fluid pressure line so as to allow fluidflow only in a direction from the valve assembly toward the hydraulicmotor, whereby the hydraulic motor can be pressurized by applyinghydraulic pressure to the fluid pressure line with the valve assembly inthe second position; and a valve control operating the valve assemblyinto one or the other of the first and second positions.
 2. The assemblyof claim 1, wherein the valve assembly comprises: a first movable valvebeing structured and arranged to prevent fluid flow from the fluidpressure line to the one end of the hydraulic motor when the valveassembly is in the first position and to allow fluid flow from the fluidpressure line to the hydraulic motor when the valve assembly is in thesecond position; and a second movable valve being positioned in thefluid drain line so as to allow fluid flow away from the hydraulic motorthrough the fluid drain line when the valve assembly is in the firstposition and to prevent fluid flow away from the hydraulic motor throughthe fluid drain line when the valve assembly is in the second position.3. The assembly of claim 2, wherein the valve assembly further comprisesa non-return valve being positioned in the fluid pressure line in serieswith the first movable valve so as to permit fluid flow therethroughonly in a direction toward the hydraulic motor.
 4. The assembly of claim3, wherein the non-return valve is positioned in the fluid pressure linebetween the one end of the hydraulic motor and the first movable valve.5. The assembly of claim 3, wherein the non-return valve is fixed inposition in the fluid pressure line.
 6. The assembly of claim 1,wherein: the coupling between the valve assembly and the one end of thehydraulic motor comprises a single fluid line; the valve assemblycomprises a movable first valve connecting to the single fluid line anda movable second valve connecting between the first valve and the fluidpressure line and the fluid drain line; the second valve couples thefirst valve to the fluid drain line and the first valve couples thesecond valve to the single fluid line when the valve assembly is in thefirst position, allowing fluid to flow in both directions through thesingle fluid line between the one end of the hydraulic motor and thefluid drain line; and the second valve couples the first valve to thefluid pressure line and the first valve couples the second valve to thesignal fluid line through a non-return valve portion when the valveassembly is in the first position, the non-return valve portion allowingfluid to flow through the single fluid line only in a direction from thefluid pressure line toward the hydraulic motor.
 7. The assembly of claim1, wherein a spring is arranged to urge the latch member toward anengaged position, the hydraulic motor acting in opposition to the springwhen extending the movable part.
 8. The assembly of claim 1, wherein thelatch member comprises a latch pin, the latch pin being retracted in thetool coupler in the disengaged position and extending from the toolcoupler in an engaged position.
 9. The assembly of claim 1, wherein thevalve assembly comprises solenoid actuated valves that are de-energizedin the first position and energized in the second position.
 10. Theassembly of claim 1, further comprising the tool coupler, the toolcoupler comprising: a coupler body relative to which the stationary partof the hydraulic motor is stationary; and the latch member being movablebetween an engaged position for engaging the tool, and a disengagedposition for disengaging from the tool.
 11. The assembly of claim 1,wherein the latch member comprises a latch pin, the latch pin beingretracted in the tool coupler in the disengaged position and extendingfrom the tool coupler in an engaged position.
 12. The coupling assemblyof claim 11, wherein the hydraulic motor is positioned on an axisdifferent from an axis defined by the latch pin.
 13. A quick-releasecoupling assembly for connecting a tool to an earth-working orconstruction equipment, comprising: a coupler body, including linkstructure for pivotally coupling to an arm of the earth-working orconstruction equipment; a latch member movable between an engagedposition for engaging the tool, and a disengaged position fordisengaging from the tool; a spring structured and arranged to provide aspring force that urges the latch member to the engaged position; ahydraulic motor having a stationary part relative to the coupler bodyand a movable part that can be extended relative to the stationary partwhen hydraulic pressure is applied to one end of the hydraulic motor,the movable part being coupled to the latch member such that extensionof the movable part urges the latch member to the disengaged position inopposition to the spring force; and a valve assembly operably coupled tothe one end of the hydraulic motor, including a first position operablycoupling the one end of the hydraulic motor to a fluid drain line toallow fluid to flow through the fluid drain line to a drain from thehydraulic motor while preventing fluid flow toward the hydraulic motor,whereby the one end of the hydraulic motor can be depressurized with thevalve assembly in the first position, and a second position operablycoupling the one end of the hydraulic motor to a fluid pressure line soas to allow fluid flow only in a direction from the valve assemblytoward the hydraulic motor, whereby the hydraulic motor can bepressurized by applying hydraulic pressure to the fluid pressure linewith the valve assembly in the second position; and a valve controloperating the valve assembly into one or the other of the first andsecond positions.
 14. The coupling assembly of claim 13, the valveassembly comprising solenoid actuated valves, the valve control beingstructured and arranged to energize the solenoid actuated valves to movethe valve assembly from the first position to the second position, andto de-energize the solenoid actuated valves to return the valve assemblyto the first position.
 15. The coupling assembly of claim 13, whereinthe valve assembly comprises: a first movable valve being structured andarranged to prevent fluid flow from the fluid pressure line to the oneend of the hydraulic motor when the valve assembly is in the firstposition and to allow fluid flow from the fluid pressure line to thehydraulic motor when the valve assembly is in a second position; and asecond movable valve being positioned in the fluid drain line so as toallow fluid flow away from the hydraulic motor through the fluid drainline when the valve assembly is in the first position and to preventfluid flow away from the hydraulic motor through the fluid drain linewhen the valve assembly is in the second position.
 16. The couplingassembly of claim 15, wherein the valve assembly further comprises anon-return valve being positioned in the fluid pressure line in serieswith the first movable valve so as to permit fluid flow therethroughonly in a direction toward the hydraulic motor.
 17. The couplingassembly of claim 16, wherein the non-return valve is fixed in positionin the fluid pressure line.
 18. The coupling assembly of claim 13,wherein: the coupling between the valve assembly and the one end of thehydraulic motor comprises a single fluid line; the valve assemblycomprises a movable first valve connecting to the single fluid line anda movable second valve connecting between the first valve and the fluidpressure line and the fluid drain line; the second valve couples thefirst valve to the fluid drain line and the first valve couples thesecond valve to the single fluid line when the valve assembly is in thefirst position, allowing fluid to flow in both directions through thesingle fluid line between the one end of the hydraulic motor and thefluid drain line; and the second valve couples the first valve to thefluid pressure line and the first valve couples the second valve to thesingle fluid line through a non-return valve portion when the valveassembly is in the first position, the non-return valve portion allowingfluid to flow through the single fluid line only in a direction from thefluid pressure line toward the hydraulic motor.
 19. An earth-working orconstruction equipment adapted for the rapid connection anddisconnection of a tool, the equipment comprising: a coupler adapted forengaging the tool, including a coupler body, a latch member movablebetween an engaged position for engaging the tool and a disengagedposition for disengaging from the tool, a spring structured and arrangedto provide a spring force that urges the latch member to the engagedposition, and a first hydraulic motor having a stationary part that isstationary relative to the coupler body and a movable part that can beextended relative to the stationary part when hydraulic pressure isapplied to one end of the first hydraulic motor, the movable part beingcoupled to the latch member such that extension of the movable parturges the latch member to the disengaged position in opposition to thespring force; a linkage adapted for engaging the coupler body; a valveassembly operably coupled to the one end of the hydraulic motor,including a first position operably coupling the one end of thehydraulic motor to a fluid drain line to allow fluid to flow through thefluid drain line to a drain from the hydraulic motor while preventingfluid flow toward the hydraulic motor, whereby the one end of thehydraulic motor can be depressurized with the valve assembly in thefirst position, and a second position operably coupling the one end ofthe hydraulic motor to a fluid pressure line so as to allow fluid flowonly in a direction from the valve assembly toward the hydraulic motor,whereby the hydraulic motor can be pressurized by applying hydraulicpressure to the fluid pressure line with the valve assembly in thesecond position; and a valve control operating the valve assembly intoone or the other of the first and second positions.
 20. The equipment ofclaim 19, wherein the valve assembly comprises: a first movable valvebeing structured and arranged to prevent fluid flow from the fluidpressure line to the one end of the hydraulic motor when the valveassembly is in the first position and to allow fluid flow from the fluidpressure line to the hydraulic motor when the valve assembly is in asecond position; and a second movable valve being positioned in thefluid drain line so as to allow fluid flow away from the hydraulic motorthrough the fluid drain line when the valve assembly is in the firstposition and to prevent fluid flow away from the hydraulic motor throughthe fluid drain line when the valve assembly is in the second position.21. The equipment of claim 20, wherein the valve assembly furthercomprises a non-return valve bieng positioned in the fluid pressure linein series with the first movable valve so as to permit fluid flowtherethrough only in a direction toward the hydraulic motor.
 22. Theequipment of claim 21, wherein the non-return valve is fixed in positionin the fluid pressure line.
 23. The equipment of claim 19, wherein: thecoupling between the valve assembly and the one end of the hydraulicmotor comprises a single fluid line; the valve assembly comprises amovable first valve connecting to the single fluid line and a movablesecond valve connecting between the first valve and the fluid pressureline and the fluid drain line; the second valve couples the first valveto the fluid drain line and the first valve couples the second valve tothe single fluid line when the valve assembly is in the first position,allowing fluid to flow in both directions through the single fluid linebetween the one end of the hydraulic motor and the fluid drain line; andthe second valve couples the first valve to the fluid pressure line andthe first valve couples the second valve to the single fluid linethrough a non-return valve portion when the valve assembly is in thefirst position, the non-return valve portion allowing fluid to flowthrough the single fluid line only in a direction from the fluidpressure line toward the hydraulic motor.
 24. The equipment of claim 19,wherein the latch member comprises a latch pin, the latch pin beingextracted in the tool coupler in the disengaged position and extendingfrom the tool coupler in the engaged position.
 25. The equipment ofclaim 19, wherein the linkage includes a pivot axis and a secondhydraulic motor, an end of the second hydraulic motor being coupled tothe coupler body to rotate the coupler body around the pivot axis, andwherein the fluid pressure line is operably coupled to one end of thesecond hydraulic motor to provide hydraulic pressure to the one end ofthe first hydraulic motor when pressure is applied to the one end of thesecond hydraulic motor and the valve assembly is in the second position.26. An assembly for urging a latch member of a tool coupler into anextended position for securing a tool to the coupler and into aretracted position for releasing the tool from the coupler, the toolbeing detachable from the tool coupler, the assembly comprising: ahydraulic motor on the coupler, the hydraulic motor having a stationarypart and a movable part that extends from the stationary part whenhydraulic pressure is applied to one end of the hydraulic motor; a latchcoupling assembly coupling between a latch member and the movable partof the hydraulic motor, structured and arranged to urge the latch memberto a retracted position when the movable part is extended; a valveassembly operably coupled to the one end of the hydraulic motor,including a first position operably coupling the one end of thehydraulic motor to a fluid drain line to allow fluid to flow through thefluid drain line to a drain from the hydraulic motor while preventingfluid flow toward the hydraulic motor, whereby the one end of thehydraulic motor can be depressurized with the valve assembly in thefirst position, and a second position operably coupling the one end ofthe hydraulic motor to a fluid pressure line so as to allow fluid flowonly in a direction from the valve assembly toward the hydraulic motor,whereby the hydraulic motor can be pressurized by applying hydraulicpressure to the fluid pressure line with the valve assembly in thesecond position; and a valve control operating the valve assembly intoone or the other of the first and second positions.
 27. The assembly ofclaim 26, wherein the valve assembly comprises: a first movable valvebeing structured and arranged to prevent fluid flow from the fluidpressure line to the one end of the hydraulic motor when the valveassembly is in the first position and to allow fluid flow from the fluidpressure line to the hydraulic motor when the valve assembly is in asecond position; and a second movable valve being positioned in thefluid drain line so as to allow fluid flow away from the hydraulic motorthrough the drain line when the valve assembly is in the first positionand to prevent fluid flow away from the hydraulic motor through thedrain line when the valve assembly is in the second position.
 28. Theassembly of claim 27, wherein the valve assembly further comprises anon-return valve being positioned in the fluid pressure line in serieswith the first movable valve so as to permit fluid flow therethroughonly in a direction toward the hydraulic motor.
 29. The assembly ofclaim 28, wherein the non-return valve is positioned in the fluidpressure line between the one end of the hydraulic motor and the firstmovable valve.
 30. The assembly of claim 28, wherein the non-returnvalve is fixed in position in the fluid pressure line.
 31. The assemblyof claim 26, wherein: the coupling between the valve assembly and theone end of the hydraulic motor comprises a single fluid line; the valveassembly comprises a movable first valve connecting to the single fluidline and a movable second valve connecting between the first valve andthe fluid pressure line and the fluid drain line; the second valvecouples the first valve to the drain line and the first valve couplesthe second valve to the single fluid line when the valve assembly is inthe first position, allowing fluid to flow in both directions throughthe single fluid line between the one end of the hydraulic motor and thefluid drain line; and the second valve couples the first valve to thefluid pressure line and the first valve couples the second valve to thesingle fluid line through a non-return valve portion when the valveassembly is in the first position, the non-return valve portion allowingfluid to flow through the single fluid line only in a direction from thefluid pressure line toward the hydraulic motor.
 32. The assembly ofclaim 26, wherein a spring is arranged to urge the latch member towardan extended position, the hydraulic motor acting in opposition to thespring when extending the movable part.
 33. The assembly of claim 26,wherein the latch member comprises a pin.
 34. The assembly of claim 26,wherein the valve assembly comprises solenoid actuated valves that arede-energized in the first position and energized in the second position.35. The assembly of claim 26, further comprising the tool coupler, thetool coupler comprising: a coupler body relative to which the stationarypart of the hydraulic motor is stationary; and the latch member beingmovable between an extended position for securing the tool, and aretracted position for releasing the tool.
 36. A quick-release couplingassembly for connecting a tool to an earth-working or constructionequipment, comprising: a coupler body, including link structure forpivotally coupling to an arm of the earth-working or constructionequipment; a latch member movable between an extended position forsecuring the tool, and a retracted position for releasing the tool; aspring structured and arranged to provide a spring force that urges thelatch member to the extended position; a hydraulic motor having astationary part relative to the coupler body and a movable part that canbe extended relative to the stationary part when hydraulic pressure isapplied to one end of the hydraulic motor, the movable part beingcoupled to the latch member such that extension of the movable parturges the latch member to the retracted position in opposition to thespring force; and a valve assembly operably coupled to the one end ofthe hydraulic motor, including a first position operably coupling theone end of the hydraulic motor to a fluid drain line to allow fluid toflow through the fluid drain line to a drain from the hydraulic motorwhile preventing fluid flow toward the hydraulic motor, whereby the oneend of the hydraulic motor can be depressurized with the valve assemblyin the first position, and a second position operably coupling the oneend of the hydraulic motor to a fluid pressure line so as to allow fluidflow only in a direction from the valve assembly toward the hydraulicmotor, whereby the hydraulic motor can be pressurized by applyinghydraulic pressure to the fluid pressure line with the valve assembly inthe second position; and a valve control operating the valve assemblyinto one or the other of the first and second positions.
 37. Thecoupling assembly of claim 36, the valve assembly comprising solenoidactuated valves, the valve control being structured and arranged toenergize the solenoid actuated valves to move the valve assembly fromthe first position to the second position, and to de-energize thesolenoid actuated valves to return the valve assembly to the firstposition.
 38. The coupling assembly of claim 36, wherein the valveassembly comprises: a first movable valve being structured and arrangedto prevent fluid flow from the fluid pressure line to the one end of thehydraulic motor when the valve assembly is in the first position and toallow fluid flow from the fluid pressure line to the hydraulic motorwhen the valve assembly is in a second position; and a second movablevalve being positioned in the fluid drain line so as to allow fluid flowaway from the hydraulic motor through the drain line when the valveassembly is in the first position and to prevent fluid flow away fromthe hydraulic motor through the drain line when the valve assembly is inthe second position.
 39. The coupling assembly of claim 38, wherein thevalve assembly further comprises a non-return valve being positioned inthe fluid pressure line in series with the first movable valve so as topermit fluid flow therethrough only in a direction toward the hydraulicmotor.
 40. The coupling assembly of claim 39, wherein the non-returnvalve is fixed in position in the fluid pressure line.
 41. The couplingassembly of claim 36, wherein: the coupling between the valve assemblyand the one end of the hydraulic motor comprises a single fluid line;the valve assembly comprises a movable first valve connecting to thesingle fluid line and a movable second valve connecting between thefirst valve and the fluid pressure line and the fluid drain line; thesecond valve couples the first valve to the drain line and the firstvalve couples the second valve to the single fluid line when the valveassembly is in the first position, allowing fluid to flow in bothdirections through the single fluid line between the one end of thehydraulic motor and the fluid drain line; and the second valve couplesthe first valve to the fluid pressure line and the first valve couplesthe second valve to the single fluid line through a non-return valveportion when the valve assembly is in the first position, the non-returnvalve portion allowing fluid to flow through the single fluid line onlyin a direction from the fluid pressure line toward the hydraulic motor.42. The assembly of claim 36, wherein the latch member comprises a pin.43. The coupling assembly of claim 42, wherein the hydraulic motor ispositioned on an axis different form an axis defined by the latch pin.44. An earth-working equipment or the like adapted for the rapidconnection and disconnection of a tool, the equipment comprising: acoupler adapted for engaging the tool, including a coupler body, a latchmember movable between an extended position for securing the tool to thecoupler and a retracted position for releasing the tool, a springstructured and arranged to provide a spring force that urges the latchmember to the extended position, and a first hydraulic motor having astationary part relative to the coupler body and a movable part that canbe extended relative to the stationary part when hydraulic pressure isapplied to one end of the first hydraulic motor, the movable part beingcoupled to the latch member such that extension of the movable parturges the latch member to the retracted position in opposition to thespring force; a linkage adapted for engaging the coupler body; a valveassembly operably coupled to the one end of the hydraulic motor,including a first position operably coupling the one end of thehydraulic motor to a fluid drain line to allow fluid to flow through thefluid drain line to a drain from the hydraulic motor while preventingfluid flow toward the hydraulic motor, whereby the one end of thehydraulic motor can be depressurized with the valve assembly in thefirst position, and a second position operably coupling the one end ofthe hydraulic motor to a fluid pressure line so as to allow fluid flowonly in a direction from the valve assembly toward the hydraulic motor,whereby the hydraulic motor can be pressurized by applying hydraulicpressure to the fluid pressure line with the valve assembly in thesecond position; and a valve control operating the valve assembly intoone or the other of the first and second positions.
 45. The equipment ofclaim 44, wherein the valve assembly comprises: a first movable valvebeing structured and arranged to prevent fluid flow from the fluidpressure line to the one end of the hydraulic motor when the valveassembly is in the first position and to allow fluid flow from the fluidpressure line to the hydraulic motor when the valve assembly is in asecond position; and a second movable valve being positioned in thefluid drain line so as to allow fluid flow away from the hydraulic motorthrough the drain line when the valve assembly is in the first positionand to prevent fluid flow away from the hydraulic motor through thedrain line when the valve assembly is in the second position.
 46. Theequipment of claim 45, wherein the valve assembly further comprises anon-return valve being positioned in the fluid pressure line in serieswith the first movable valve so as to permit fluid flow therethroughonly in a direction toward the hydraulic motor.
 47. The equipment ofclaim 46, wherein the non-return valve is fixed in position in the fluidpressure line.
 48. The equipment of claim 44, wherein: the couplingbetween the valve assembly and the one end of the hydraulic motorcomprises a single fluid line; the valve assembly comprises a movablefirst valve connecting to the single fluid line and a movable secondvalve connecting between the first valve and the fluid pressure line andthe fluid drain line; the second valve couples the first valve to thedrain line and the first valve couples the second valve to the singlefluid line when the valve assembly is in the first position, allowingfluid to flow in both directions through the single fluid line betweenthe one end of the hydraulic motor and the fluid drain line; and thesecond valve couples the first valve to the fluid pressure line and thefirst valve couples the second valve to the single fluid line through anon-return valve portion when the valve assembly is in the firstposition, the non-return valve portion allowing fluid to flow throughthe single fluid line only in a direction from the fluid pressure linetoward the hydraulic motor.
 49. The equipment of claim 44, wherein thelatch member comprises a pin.
 50. The equipment of claim 44, wherein thelinkage includes a pivot axis and a second hydraulic motor, an end ofthe second hydraulic motor being coupled to the coupler body to rotatethe coupler body around the pivot axis, and wherein the fluid pressureline is operably coupled to one end of the second hydraulic motor toprovide hydraulic pressure to the one end of the first hydraulic motorwhen pressure is applied to the one end of the second hydraulic motorand the valve assembly is in the second position.